DESCRIPTION: The goal of our research project is to produce safe, inexpensive and easily administered apple fruit-based vaccine which can be used in humans for immunization against Dental caries, (Streptococcus mutatis). We will accomplish this by developing transgenic apple (Malus domestica) producing the edible vaccine reagent. Specific Aims are to obtain plant binary expression vectors to carry chimeric protein consisting of the saliva-binding region (SBR) of S. mutans Agl/ll coupled to cholera toxin (CT) A2 and B subunits (CTA2B) and/or glucan-binding (GLU) protein of glucosyltransferases (GTF) for Agrobacterium-mediated transformation, to obtain transgenic apple line to express SBR-CTA2B and/or GLU genes. We will design the plant binary expression vector for Agrobacterium-mediated plant transformation to deliver SBR-CTA2B and/or GLU genes to apple genome. Hypotheses to be tested are that the SBR-CTA2B and/or GLU are expressed in transgenic apples and both SBR-CTA2B and GLU proteins expressed in apple synergistically elicits protective immune responses in mice. First, we will obtain transgenic apple plant to produce antigenic SBR-CTA2B and GLU proteins and quantify the amount of SBR-CTA2B and/or GLU proteins produced in in vitro transgenic apples. Protective immune response in mice will be observed in mice immunized by transgenic apple leaf producing SBR-CTA2B and/or GLU proteins. We will test if the SBR-CTA2B and/or GLU proteins expressed in transgenic apple leaf tissue induces serum and fecal IgG and IgA, and salivary IgA responses in mice. We also will investigate whether there is synergy between SBR-CTA2/B and GLU oral immunization with respect to protection to Dental caries in mice. The long range goal is to develop a potential and useful fruit-based delivery system for a vaccine against Dental caries. The proposed research will initiate a novel approach to develop a plant fruit-based vaccine delivery system for a pharmaceutical vaccine against Dental caries and other infectious diseases.